Design of a new line in treatment of experimental rheumatoid arthritis by artesunate

This study was aimed to evaluate the therapeutic potency of a new antimalarial drug, artesunate, in an experimental model of rheumatoid arthritis. Collagen-induced arthritis (CIA) was induced in Lewis rats.The intraperitoneally administration of artesunate (ARS) and methotrexate (MTX) were started on day 25 postimmunization and continued until final assessment on day 35. During this period, clinical examination was intermittent. The anticollagen type II antibody (CII Ab) and nitric oxide synthesis were measured. The paws and kness were then removed for histopathology and radiography assay. The biocompatibility of ARS and MTX were assessed using fibrosarcoma cell line. Our results showed that i.p. injection of artesunate to arthritic rats induced a significant reduction in paw edema. This beneficial effect was associated with a significant decrease in anti-CII antibody response compared with untreated rats. Histopathological assessment showed reduced inflammatory cells infiltrate in joints of treated rats, and tissue edema and bone erosion in the paws were markedly reduced following ARS therapy. Moreover, our radiographic results paralleled histological findings. Cytotoxicity analysis of ARS showed greater tolerability compared with MTX. Treatment with ARS significantly diminished nitric oxide formation in treated rats compared with untreated controls. Our findings revealed the therapeutic efficacy of artesunate in experimental rheumatoid arthritis compared with a choice drug (methotrexate). This result may recommend it as a second-line drug in the treatment of rheumatoid arthritis.     

Importance of kelch 13 C580Y mutation in the studies of artemisinin resistance in Plasmodium falciparum in Greater Mekong Subregion

The mortality caused by Plasmodium falciparum was reduced by Artemisinin (ART) and ART combination therapy (ACT). However, Artemisinin resistance (ART-R) emerge during 2008 in Cambodia and spread to Greater Mekong Subregion (GMS). ART-R was confirmed not to spread to India, a gateway to whole Africa. The whole genome sequencing approach of P. falciparum assumed the k13 gene encoded Kelch protein was discovered to be associated with ART-R. Of the single nucleotide polymorphisms (SNPs) of k13 gene, C580Y mutant was commonly dominant in Cambodia, Myanmar, Thailand, Laos and Vietnam and assumed to be one of strong molecular markers for ART-R in P. falciparum isolates in GMS. Literatures published between 2017 and 2018 were reviewed in this work. F446I is observed to be doubtful molecular marker as ART-R marker. Transgenic experiment showed that parasite with F446I mutation displayed prolonged clearance in respond to ART while C580Y was applied as positive control mutant. Furthermore, study of C580Y allele in four countries Cambodia, Thailand, Laos resulted in single origin whereas the parasite with this allele showed multi-origin in three Provinces of Vietnam. As artemisinin was short acting drug, the role of long acting partner drug was studied by using transgenic C580Y mutant and C580 to leave recrudescent P. falciparum. Recently, there was treatment failure with ACT in some countries in GMS. In this review, the importance of C580Y mutation in the study of ART-R was discussed.     

Phytochemical licochalcone A enhances antimalarial activity of artemisinin in vitro

Resistance to synthetic first-line antimalarial drugs is considered to be a major cause of increased malaria morbidity and mortality. Use of artemisinin-based combination therapies (ACTs) is being encouraged to reduce the malaria mortality in areas of falciparum resistance. Artemisinin is a natural product at times in short supply. With projected rise in demand of artemisinin there is an unmet need for alternate ACTs. Novel compounds that reduce dependance on artemisinin are required. In vitro cultures of Plasmodium falciparum provide a screen system for identifying and evaluating new drug combinations. Interactions of two phytochemicals, artemisinin and licochalcone A, has been studied against synchronized erythrocytic stages of chloroquine-sensitive 3D7 and chloroquine-resistant RKL 303 strains of P. falciparum. These two compounds in combination show synergistic antiplasmodial activity in vitro on these strains. Artemisinin but not licochalcone A interferes with hemozoin formation. Neither of the phytochemicals alone or in combination obstructs sorbitol-induced hemolysis.     

Cytotoxic Activity of Artemisinin Derivatives Against Cholangiocarcinoma (CL-6) and Hepatocarcinoma (Hep-G2) Cell Lines

Cytotoxic activity of artemisinin and derivatives in the presence and absence of holo-transferrin andexpression of genes involved in resistance of cancer cells were investigated in human cholangiocarcinoma (CL-6)and hepatocarcinoma (Hep-G2) cell lines in vitro. After incubation with the test drugs and 5-fluorouracil (5-FU) cytotoxicity was asessed by MTT assay. RNA was extracted after 24 hour exposure to holo-transferrin forinvesstigation of the expression of transferrin receptor 1 (TDR1), multidrug resistance 1 (MDR1), multidrugresistance protein 1 (MRP1), multidrug resistance protein 2 (MRP2), and multidrug resistance protein 3 (MRP3).The median IC50 of artemisinin, artesunate, β-artemeter, dihydroartemisinin and 5-FU were as follows: CL-6:339, 131, 354, 75, and 377 μM, respectively; Hep-G2: 268, 50, 233, 29, and 1,380 μM. Exposure to holo-transferrinhad no influence on sensitivity of either cell line to artemisinin derivatives, but resulted in a 3-fold increase inthe expression of TR1 and MDR1, and a 2-fold increase in the expression of MRP1 and MRP2 in CL-6 cells.With Hep-G2, a 3-fold increase in the expression of MDR1 and MRP3 and a 2-fold increase in expression ofMRP2 were observed. Dihydroartemisinin exhibited the most potent cytotoxic activity against both cell linesand holo-transferrin caused different patterns of expression of resistance-associated genes.     

Preparation of the nanostructured lipid carriers of artemisinin and its pharmacokinetic evaluation

Artemisinin (ART) is a widely used active drug for malaria, including severe and cerebral malaria. However, its therapeutic efficacy is affected by its lower bioavailability. In the present study, nanostructured lipid carriers (NLCs) were proposed as carrier of ART to improve pharmacokinetic properties of the drug. ART-NLC was prepared by high-pressure homogenization based on orthogonal design. The particle size, zeta potential, encapsulation efficiency (EE) and percentage of drug loading (DL) of ART-NLC were (53.06±2.11) nm, (–28.7±3.59) mV, 73.9%±0.5% and 11.23%±0.37%, respectively. ART-NLC showed the sustained release characteristics and scarcely the hemolysis effect on human red blood cells. The pharmacokinetics of ART-NLC for rats after tail intravenous injection (i.v) or intraperitoneal injection (i.p) were investigated by liquid chromatography-tandem mass spectroscopy (LC-MS/MS). And ART solution was designed as control preparation. For rats of i.v groups, the AUC0–∞ ((707.45±145.65) ng·h/mL) of ART-NLC were significantly bigger than that of ART ((368.98±139.58) ng·h/mL). The MRT ((3.38±0.46) h) of ART-NLC was longer than that of ART ((1.39±0.61) h). And similar results were observed for rats of i.p groups. The AUC0–∞ ((1233.06±235.57) ng·h/mL) and MRT ((4.97±0.69) h) of ART-NLC were both bigger than those of ART, which were (871.17±234.03) ng·h/mL) and (1.75±0.31) h), respectively. Compared with ART, ART-NLC showed a significant increase in AUC0–∞ (P<0.05) and MRT (P<0.001) for both i.p and tail i.v administrations.     

二蒿乙醚基胺马来酸盐诱导活性氧产生促进SU-DHL-4细胞凋亡

目的:研究青蒿素衍生物二蒿乙醚基胺马来酸盐(SM1044)诱导活性氧产生促进SU-DHL-4细胞凋亡的机制。方法:流式细胞术检测SM1044对SU-DHL-4细胞活性氧的水平影响;流式细胞术检测SU-DHL-4细胞的凋亡情况及蛋白质印迹检测凋亡相关蛋白的表达;免疫荧光技术检测细胞内钙离子的荧光强度及蛋白质印迹检测内质网应激相关蛋白CCAAT/增强子结合蛋白(C/EBP)腺苷环磷酸反应元件结合转录因子同源蛋白(CHOP)的表达。结果:SM1044可诱导SU-DHL-4细胞产生活性氧,且具有时间依赖性(r=0.951,P=0.003);SM1044可诱导SU-DHL-4细胞凋亡及凋亡相关蛋白的活化,使用N-乙酰半胱氨酸(NAC)清除活性氧后,SM1044诱导SU-DHL-4细胞凋亡的作用被抑制(P<0.01),凋亡相关蛋白的表达也被抑制;SM1044可促进SU-DHL-4细胞内钙离子水平的升高以及内质网应激相关蛋白CHOP的表达,使用NAC清除活性氧后,钙离子水平的升高以及CHOP蛋白的表达被抑制。结论:SM1044可通过诱导SU-DHL-4细胞产生活性氧促进SU-DHL-4细胞凋亡,其机制可能与活性氧激活钙离子-内质网应激有关。     

双氢青蒿素抑制核因子κB受体激动剂配体诱导RAW264.7细胞分化破骨细胞的研究

目的 探讨双氢青蒿素(DA)对核因子κB受体激动剂配体(RANKL)诱导RAW264.7细胞形成破骨细胞的影响。方法 通过细胞计数试剂盒(CCK-8)确定不同浓度(1、5、10、50、100、200 μmol/L)DA对RAW264.7细胞的生存影响。分别用50 ng/mL RANKL及50 ng/mL RANKL+5、10、50、100 μmol/L DA诱导RAW264.7细胞形成破骨细胞,共3 d。对形成的破骨细胞用抗酒石酸酸性磷酸酶(TRAP)染色并计数,TRAP染色阳性且细胞核数目＞3个认为是成熟的破骨细胞。50 ng/mL RANKL及50 ng/mL RANKL+10、100 μmol/L DA培养RAW264.7细胞24 h,用Trizol试剂提取总RNA,并使用荧光实时定量PCR检测破骨细胞分化相关基因NFATc1、c-fos及Cathepsin K的表达。结果 1、5、10、50、100 μmol/L DA对RAW264.7细胞毒性较小,细胞存活率均＞90%。TRAP染色显示,5、10、50、100 μmol/L DA可以减少RANKL诱导成熟破骨细胞的数目,并呈剂量依赖关系(F=139.156, P＜0.01)。实时荧光定量PCR结果显示,10、100 μmol/L DA具有下调破骨细胞分化关键基因NFATc1和c-fos表达的作用,且100 μmol/L抑制作用比10 μmol/L明显,但两种浓度DA对Cathepsin K的表达无明显影响。结论 DA对RAW 264.7细胞毒性较低,通过下调RAW 264.7细胞NFATc1和c-fos基因表达抑制RANKL诱导破骨细胞形成。DA可以作为治疗骨质破坏性疾病的潜在药物。     

青蒿素及其衍生物抑制K562细胞生长作用比较

【目的】比较青蒿素、青蒿琥酯、双氢青蒿素对K562细胞生长的抑制作用。【方法】体外培养白血病K562细胞,3种药物作用于细胞,观察不同浓度的药物作用不同时间后,细胞数目的变化。【结果】3种药物在浓度为10-4、10-5、10-6mol/L时,细胞生长受到显著抑制,并呈剂量依赖性,且不同药物其抑制作用强弱有明显差异。【结论】青蒿素、双氢青蒿素及青蒿琥酯可以抑制肿瘤细胞K562的生长,且相同浓度下青蒿琥酯的作用最强。